Bronchoscopic repair of air leaks in a lung

ABSTRACT

Systems and devices for minimally invasively treating an air leak in a lung comprise the steps of detecting an air leak in a lung; locating an airway in fluid communication with the air leak, introducing a bronchoscope into a patient&#39;s airway to a position adjacent the target section and occluding an airway upstream of the air leak for a period of time. The airway occlusion device is preferably removed after the air leak has substantially permanently healed. The occluding device may be a one-way valve. The occluding device may also comprise strut members and anchors that penetrate an airway wall.

CLAIM OF PRIORITY

This application is a continuation application of U.S. patentapplication Ser. No. 13/853,433, filed Mar. 29, 2013, and incorporatedin its entirety by reference herein, which is a continuation applicationU.S. patent application Ser. No. 13/005,444, filed Jan. 12, 2011, nowissued as U.S. Pat. No. 8,444,690 and incorporated in its entirety byreference herein, a continuation of U.S. patent application Ser. No.12/398,122, filed Mar. 4, 2009, now issued as U.S. Pat. No. 7,887,585and incorporated in its entirety by reference herein, which is adivisional application of U.S. patent application Ser. No. 10/745,401,filed Dec. 22, 2003, now issued as U.S. Pat. No. 7,533,671 andincorporated in its entirety by reference herein, and which claims thebenefit of U.S. Provisional Application No. 60/493,933, filed Aug. 8,2003, which is incorporated in its entirety by reference herein. Any andall priority claims identified in the application data sheet, or anycorrection thereto, are hereby incorporated by reference under 37 CFR1.57.

BACKGROUND

Field of the Invention

The invention relates in general to the field of pulmonary treatments,and specifically to a bronchoscopic method of treating air leaks in alung.

Description of the Related Art

Air leaks that allow air inhaled through a person's mouth to leak out ofa lung and into the pleural cavity or other cavity within the person'schest are frequently experienced by people with severe emphysema orother chronic pulmonary disorders. In the pathology of air leaks, thereis a disruption of the lung pleura, parenchyma (tissue) and airwaysproducing abnormal direct communication of inspired air to the thoraciccavity. Also, air leaks are a common complication of lung surgery andlung trauma. This undesired flow of air into the pleural cavity canultimately lead to severe pneumothorax and collapse of the lungs causedby the loss of the normal pressure differential between the pleuralcavity and the lung. Alveolar-pleural fistulas refer to a communicationbetween the lung parenchyma and the pleural space and is commonlyobserved after trauma or in patients with weak and diseased lungs.Broncho-pleural fistulas are communications between the mainstreamlobar, lobar or segmental bronchus and the pleural space and in manycases are consequence of surgery.

Typical treatment of air leaks involves the placement of chest tubesconnected to a water trap/seal system to allow the leaked air to bedrained from the pleural cavity in order to prevent tension pneumothoraxand hopefully reverse the collapse of the lung. Some air leaks healquickly within a few days without the need for intervention. Others,however, can take weeks or longer, while still others ultimately requiresurgery to resolve the leak.

Some bronchoscopic solutions have been developed for treatment of airleaks. For example the use of various plugs, glues, adhesives, andsealing agents have been used, with limited success. One problem withsuch occlusive devices is that they tend to dislodge from the patient'slung when the patient coughs. Thus, there remains a need forimprovements to bronchoscopic air leak treatment procedures and systems.

SUMMARY OF THE INVENTION

The present invention addresses that need. Thus, one embodiment of animproved system for treating air leaks comprises means for identifyingand sizing the lung airways that lead to the air leak, means foroccluding those select airways to permit the leak to heal, and means fordelivering and removing the occluding device as desired. An improvedmethod comprises identifying and sizing lung airways that lead to theair leak, including identifying the fistula causing the air leak,delivering an occluding device to one or more of those airways to permitthe air leak to heal, and removing the occluding device after the airleak has healed.

With regard to the present inventive system, the means for identifyingthe lung airways to be occluded is preferably, but not necessarily, aballoon catheter adapted to be used for identification and mapping ofthe airways communicating with a disrupted area of a lung. The ballooncatheter may also be used as well to size the identified airways toselect an appropriately sized intra-bronchial occlusion device fortreatment. In the preferred embodiment, the occlusion device is aone-way valve expandable into place within the select airways, such asthe devices disclosed in co-pending application Ser. Nos. 09/951,105;10/317,667; 10/103,487; 10/124,790; 10/143,353 and 10/150,547, all ofwhich are incorporated herein by reference. In an alternativeembodiment, the occlusion device need not be a valve, but can be adevice that precludes any fluid communication therethrough. In eithercase, it is preferred that the occlusion device include anchoring means,such as barbs, to preclude dislodging of the occlusion device oncepositioned in place. Valve action also minimizes dislodging bypermitting the venting of some back pressure otherwise built up when thepatient coughs.

If desired, medicants can be embedded in and/or coated on the occludingdevice. Alternatively or in addition, once the occluding device is inplace, medicants could be injected into the airway on a distal side ofthe device to facilitate and/or accelerate the sealing and closure ofthe leaks.

The methods described herein involve minimally invasive procedures fortreating air leaks in a patient's lung, including conditions created byalveolar-pleural fistulas and broncho-pleural fistulas. There are manyadvantages to treating an air leak by deploying an occlusion device in abronchial passageway. Providing a bronchial occlusion upstream from anair leak in accordance with the present methods can cause the airleakage out of the lung to be slowed, or preferably stopped. This willgenerally result in a reduction, elimination or prevention ofpneumothorax caused by the air leak. At the same time, the reduction orelimination of airflow through the fistula is expected to allow thetissue surrounding the fistula to heal more quickly, thereby permanentlyclosing the air leak.

As used herein, the term “air leak” is a broad term, and is used in itsordinary sense and refers, without limitation, to any flow of airexiting a lung by any unintended or undesired path. Also, as usedherein, the term “fistula” is a broad term, and is used in its ordinarysense and refers, without limitation, to an abnormal passage providingfluid communication between a lung airway an another organ or cavitywithin a patient. For example, a fistula as referred to herein maygenerally include peripheral bronchopleural fistulas, bronchocutaneousfistulas, or any other fistulas causing an air leak. Such fistulas canbe caused by trauma, thoracic surgery, irradiation, or disease such asnecrotizing pneumonia, empyema, emphysema, etc. The methods and devicesdescribed herein are intended to be useful in treating air leaks,regardless of their specific cause.

As used herein, the terms “occlusion device” and “intra-bronchialocclusion device” are broad terms, and are used in their ordinary senseand refer, without limitation, to any object deployed in an airway thatoccludes the flow of air in either inspiratory or expiratory directions(or both) through the airway in which the device is deployed. The termis intended to include valves, plugs, ball bearings, injectableoccluding substances such as glues or polymers, or any other objectcapable of occluding an airway.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a pair of lungs.

FIG. 2 is a cross-section of a lung portion schematically illustrating adelivery and deployment system.

FIG. 3 is a flow chart illustrating one embodiment of a method ofmapping and selecting airways in fluid communication with an air leak.

FIG. 4 is a perspective view of one embodiment of an intra bronchialocclusion device.

FIG. 5 is a cross-sectional view of the occlusion device of FIG. 4.

FIG. 6 is a side section view of an airway with an occlusion devicedeployed therein.

FIG. 7 is a detail view of a portion of the occlusion device of FIG. 6.

FIG. 8 is a front view in partial cross-section of the portion of FIG.7.

DETAILED DESCRIPTION

Reference is now made to the figures wherein like parts are designatedwith like numerals throughout. Referring to FIG. 1, airflow in a lung 10to be treated generally follows a path from the trachea 12, through themain branch bronchial tubes 14, then through the first generationsub-bronchial tubes 16 and ultimately to the numerous tiny bronchioles18. The bronchioles 18 lead to alveolar sacs which function to transferoxygen from the air to the bloodstream. The outer surface 20 of the lungcomprises the parenchyma, sub-serous coat and serous coats that seal airwithin the lung. Air leaks as described herein can be caused by a breachof the parenchyma, the sub-serous coat and/or the serous coat thatcreates an abnormal passage between the interior air-passageways of thelung and the fluids and tissues external to the lung.

As used herein, the term “generation” is a broad term, and is used inits ordinary sense and refers, without limitation, to a location of anairway within a lung in terms of a number of bifurcations that aretraversed in accessing a particular airway from the mainstem bronchus.For example, as shown in FIG. 9, the trachea 12 branches into the rightand left mainstem bronchi 14. The mainstem bronchi 14 then branch into aplurality of first generation airways 16. Each of these first generationairways 16 then also branches into second generation airways 22 which inturn branch into third generation airways 24, and so on. As will beclear to the skilled artisan, the airways get progressively smaller indiameter as they progress to higher generations until the airwaysterminate in the alveoli.

With reference to FIGS. 1-3, the preferred method comprises the steps ofdetecting the presence of an air leak in a lung, including identifyingat least one airway leading to a fistula causing the air leak; selectinga target location; introducing a means for delivering an intra-bronchialocclusion device to the target location; optionally injecting asubstance into the airway distal to the target location, andsubstantially limiting air leakage by temporarily deploying one or moreocclusion devices for a sufficient time to allow the tissue surroundingthe fistula to heal and close the fistula, and finally removing theocclusion device at some later time.

Methods for detecting the presence of air leaks in a human lung aregenerally well known, and any suitable method can be used in connectionwith the treatment systems and methods described herein. For example,the presence of an air leak in a lung can be identified by a physicianon the basis of the patient's symptoms. In addition, some mechanicalsystems have been developed for the purpose of identifying air leaks inpatients after thoracic surgery. For example, one such system isdescribed in co-owned and co-pending patent application Ser. No.10/259,007, filed on Sep. 26, 2002 which is incorporated herein byreference.

A means for identifying an airway in fluid communication with thefistula and for selecting a target location at which to deploy anintra-bronchial device can include any suitable device or system capableof doing so. In some embodiments, such systems involve testing airwaysin a trial-and-error manner by occluding a test airway and checking fora decrease in a flow rate and/or a volume of air leakage during eachbreath. The patient will often have a chest tube and a water trap oranother suitable system in place to allow excess air in the patient'schest cavity to be drained. When the air-flow through the fistula isoccluded, the lack of air-flow through the water trap (or other drainagesystem) can be observed, such as by a lack of, or a decrease in thenumber of bubbles in a water trap system.

According to one embodiment, an approximate location of a fistula isdetermined by x-ray or other imaging system, and then a bronchoscope isdirected to a portion of the interior of the lung that is believed to beupstream of the fistula. A balloon catheter can then be directed througha working channel of the bronchoscope such that the inflatable balloonextends from the distal end of the bronchoscope. The balloon catheter ispreferably configured such that inflation of the balloon is capable ofcompletely occluding the airway in which it is positioned, therebyallowing a clinician to identify airways in fluid communication with theair leak and to determine whether the location of the balloon is asuitable location for an occlusion device. This determination isgenerally made by observing a cessation of, or a reduction in, theairflow through the chest tube and drainage system when the balloon isinflated to occlude the potential target airway. The reduction orcessation of air-flow through the drainage system (visible as areduction in the number of bubbles in a water trap, for example)generally indicates that the undesired airflow through the fistula andinto the pleural cavity has decreased or stopped. In some situations, itmay be particularly beneficial to occlude a plurality of airways inorder to reduce air leakage sufficiently to treat one or more fistulas.In general, it is desired that the occlusion device, or devices beplaced as close to the periphery of the lung as possible. The closer tothe actual fistula that an intra-bronchial device can be deployed, thesmaller the amount of healthy lung tissue that will be occluded.

While attempting to select a suitable target location, the inflatableballoon 44 (see FIG. 2) used to temporarily occlude the airway can alsobe simultaneously used to measure a diameter of the airway at thepotential target location and any other test locations identified duringthe process of selecting a target location. For example, when arelationship between a known volume of fluid used to inflate a balloonand a cross-sectional area of the balloon is known, the diameter of anairway at a proposed target location can be determined by measuring avolume of fluid required to inflate the balloon sufficiently to occludethe ariway and to cause a reduction in the airflow through the drainagesystem. Further systems and methods for measuring a size of an airwaywith an inflatable balloon are described, for example, in co-owned andco-pending application Ser. No. 10/254,392 filed on Sep. 24, 2002 andSer. No. 10/196,513 filed on Jul. 15, 2002, both of which areincorporated herein by reference and made part of the presentapplication.

With reference now to FIGS. 1-3, embodiments of methods of locating andmapping airways in fluid communication with an air leak in a patient'slung will be described. According to one embodiment, a method ofidentifying and mapping airways in fluid communication with an air leakincludes delivering a bronchoscope 30 into a first bronchial passageway32 that is believed to be in communication with the leak. The firstpassageway 32 to be tested is typically a first or second generationairway. A balloon catheter 40 such as those described above can be fedthrough the working channel 42 of the bronchoscope 30 until theinflatable balloon 44 is in an airway 32. The balloon 44 is theninflated sufficiently to occlude airflow through the airway 32 to betested. The balloon 44 is left in place while the patient inhales andexhales a few times.

FIG. 3 is a flow chart schematically illustrating one embodiment of amethod for identifying and mapping airways in fluid communication withan air leak in a patient's lung. A clinician begins by selecting 50 afirst test airway (a first generation airway in the illustratedexample). The clinician then guides a bronchoscope 30 and/or a ballooncatheter 40 to the selected test airway, and the clinician inflates theballoon 44 and occludes 52 the test airway. To determine whether or notthe test airway is in fluid communication with the air leak, theclinician checks 54 for a decrease in a rate and/or a per breath volumeof air leakage (using any suitable method or means). If the cliniciandoes not detect 56 a decrease in air leakage, the clinician can repeatthe selecting 50, occluding 52 and checking 54 steps until a firstgeneration airway in fluid communication with the air leak isidentified.

Once the checking step 54 returns a positive result 58 (i.e. a decreasein air leakage is detected), the clinician will advance the catheter toselect a second 60, typically smaller, test airway (a second generationairway in the illustrated example). Once a second generation test airwayis selected 60, it can be occluded 58 by inflating the balloon, and theclinician can check 64 for a further reduction in air leakage. Third,fourth and further generation airways in fluid communication with an airleak can be identified in much the same manner as described above withrespect to the first and second. For example, when a second airway isoccluded 62, a clinician can check for a decrease in air leakage 64. Ifthe clinician finds no reduction in leakage 66, he/she can select 60another second generation test airway and occlude it 62. Once a positiveresult 68 is returned, a clinician might determine that an optimumairway has been found, and he/she may select a target location 70 fordeployment of an occlusion device.

In this way, a clinician can progressively narrow down the selection ofairways in order to identify an optimum location for treating the airleak. Once a clinician has identified an optimum airway for treating theair leak, the clinician can select 70 that airway as a target locationfor the delivery of an intra-bronchial occlusion device as describedherein.

In one embodiment, an optimum target location is preferably the smallestpossible airway in fluid communication with the air leak, and in whichan occlusion device can be deployed. In an alternative embodiment, anoptimum target location is the airway which, when occluded, causes amaximum reduction in a rate of air leakage, while occluding a minimum ofhealthy lung tissue. In further embodiments, still other criteria can beapplied for the selection of an optimum target location. In someembodiments, a clinician might determine a need for a plurality ofocclusion devices, in which case, the clinician will typically identifya plurality of target locations.

As suggested above, the volume of fluid injected into the balloon 44during the selection and mapping process can be correlated to a size ofan occlusion device to be deployed at a selected target location. Inthis way, the occlusion device to be delivered can advantageously beselected to match the diameter of the target airway as closely aspossible.

Additionally, throughout the selection process, the airways can also bemapped in terms of their size, generation, and their relative location.For example, each time an airway is occluded 52, 62, the volume of fluidinjected into the balloon 44 can be recorded and correlated to aninternal diameter of the airway at the test location. This sizeinformation can be useful for creating a graphic, schematic, ormathematic “map” of the airways in a patient's lung. Size informationcan also be combined with information relating to the generation of anairway, and where the airway is located relative to other known airways.

Thus, by measuring diameters of airways at a plurality of locationsduring the selection process, and/or by recording the location of eachof the test locations, a map of the airways in fluid communication withan air leak in patient's lung can be developed. In mapping the airwaysin a patient's lungs, a clinician can gather information relating to thelocation of airways, such as by recording a length of the bronchoscope30 and/or balloon catheter 40 advanced into the patient to reach a giventest location, as well as a chosen direction each time a bifurcation isencountered. All of this location and size information can then becompiled in a three-dimensional map, a two-dimensional schematic map, orsimply as a series of coordinates for the purpose of identifying thelocations of each of the test points. Such a map can be useful in laternavigating a catheter through a patient's airways to a target location(or any other recorded point) such as for removing an occlusion device,for later placing additional occlusion devices, or for other proceduresrequiring a clinician to navigate a bronchoscope through a patient'sairways to a known point.

Once a target location has been selected 70, the location can be markedsuch that a clinician can later place an intra-bronchial occlusiondevice at substantially the same location that was measured with theinflatable balloon. Such marking can be performed by injecting abiocompatible visible ink or other visually-identifiable substance.Alternatively, the marking of a target location can be accomplished byproviding markings on proximal ends of the balloon catheter and thedelivery catheter. Alternatively still, a target location can be markedin such a way as to be visible via X-ray or other visualizing system.Alternatively, a target location can be recorded in a graphical ormathematical map which can be later followed by a clinician in order toguide a bronchoscope to deliver an occlusion device at apreviously-selected target location.

The occlusion device is configured to substantially preclude inspiredair or fluid downstream of said device, and in one embodiment comprisesa one-way valve that allows the flow of fluid, whether gas or liquid, inone direction and substantially precludes fluid flow in an oppositedirection. According to one embodiment, a one-way valve may beconfigured in the shape of an umbrella comprising an impermeablemembrane surrounding a frame that is configured to exert radial forcesagainst the wall of the airway passage. Such an arrangement wouldpreclude substantial inspired air to the lung downstream of theplacement of the device, but permit some limited fluid flow upstream,such as experienced with mucoscilliary transport or exhaled air. Inanother configuration, the one-way valve may comprise a stent-supportedvalve comprising an expandable support member mounted to a valve member.In still another configuration, the device may comprise an expandableframe with spherical or spheroid (egg) shape partially or completelycovered with a membrane, such as the device described in co-pendingapplication Ser. No. 09/951,105 identified above.

The occlusion device can be one of many devices suitable for occludingthe flow of air in an anatomical lumen. For example, co-owned U.S. Pat.No. 6,293,951 to Alferness et al. shows and describes a number ofdevices for unidirectionally and bidirectionally occluding airflowthrough an airway. Additionally, co-owned and co-pending U.S. patentapplication Ser. No. 10/143,353 filed on May 9, 2002 shows and describesembodiments of a one-way valve that can also be used to treat an airleak while advantageously allowing mucous and other fluids to be movedproximally past the valve. Further embodiments of implantable one-wayvalves are described in co-owned and co-pending U.S. patent applicationSer. No. 09/951,105 to Alferness et al. filed on Sep. 11, 2001; Ser. No.10/103,487 to Alferness et al. filed on Mar. 20, 2002; Ser. No.10/124,790 to DeVore filed on Apr. 16, 2002; and Ser. No. 10/150,547 toDillard et al., filed on May 17, 2002. The entire disclosures of theabove patents and applications are incorporated herein by reference andmade part of the present disclosure.

In providing an occlusion device to be deployed in an airway fortreating an air leak in a lung, it is believed to be substantiallyadvantageous to provide a device configured to act as a one way valve byallowing air to flow past the device in an expiratory (or proximal)direction, while occluding airflow in an inspiratory (or distal)direction. For example, a one-way valve deployed in an airway forsealing an air leak has substantially less chance of being dislodged bythe patient's coughing. In the case of a complete occlusion, a patient'scough will typically cause a substantial amount of air pressure to bebuilt up at the distal edge of the occlusion relative to a pressure onproximal side. If this pressure differential is high enough, theocclusion device can become dislodged, and can actually be coughed outof the patient's mouth. In addition, the expansion and contraction ofthe lung tissue surrounding a deployed occlusion device can cause someocclusion devices to migrate within the airway, and potentially tobecome dislodged. By allowing expired air to flow out past the device,the pressure differential between the distal side and the proximal sideof the device will typically not reach a level sufficient to dislodgethe device. Nonetheless, by employing anchors, even a non-valvularocclusion device can be maintained in the desired target position.

Additionally, an occlusion device to be deployed in an airway for thetreatment of an air leak is preferably configured to have a minimumeffect on the lung's mucosciliary transport. For example, as mentionedabove, the co-owned and co-pending application Ser. No. 10/143,353teaches embodiments of occlusion devices which could be used inaccordance with the methods described herein.

One preferred embodiment of an occlusion device, illustrated in FIGS.4-8, comprises an intra-bronchial valve (IBV) 140 for use in treating anair leak. The illustrated valve 140 is preferably generallyumbrella-shaped and comprises a frame 142 having a plurality of struts144 and preferably a plurality of anchor members 150, all of which arejoined together at a central joint 152. The struts 144 are generallyconfigured to support a membrane 160 on their outer surface 162. The IBV140 is also illustrated as including a central connector rod 170 adaptedto be engaged in deploying and removing the IBV 140.

As illustrated, the frame 142 may comprise a shape similar to anassymetric hourglass, with one end provided with a membrane andconfigured to act as a valve member, and the other end configured toanchor the device against axial movement within an airway. According toone embodiment, the frame 142 (including the struts 144 and the anchors150) can be made of a single tubular piece of a superelastic materialsuch as Nickel-Titanium (also known as NiTi or NITINOL). The frame 142can be machined, molded, or otherwise formed to create the desiredfunctional elements as shown and described herein. In one embodiment, ahollow tube of NiTi is machined to form the struts 144 and anchors 150.The struts and anchors can be formed from the solid tube by making axialcuts along the tube to create the desired number of struts 144 andanchors 150 while leaving an uncut ring section 172 between the struts144 and the anchors 150. The struts 144 and anchors 150 can then be bentinto the desired shapes in such a way that the frame will naturallyassume the desired expanded shape at temperatures expected in an airway.Alternatively, the frame 142 can be made from sections of wire bent intothe desired shapes. The skilled artisan will recognize that superelasticand/or “shape memory” materials such as NiTi typically require uniquemanufacturing processes involving substantial amounts of heat treating.The details of such manufacturing processes will be understood by thoseskilled in the art of Nickel-Titanium manufacturing.

The connector rod 170 typically includes a base 174 that is sized to beattached to the ring section 172 of the frame 142 at the central joint152. The attachment of the connector rod 170 to the frame 142 can beaccomplished by press fitting the base 174 within the ring section 172of the frame 142. If desired the connection between the rod base 174 andthe ring section 172 can further include adhesives, welds, or any othersuitable fastening means.

The frame 142 made of a superelastic material such as NiTiadvantageously allows the IBV to be compressed to occupy a very smallaxial shape during delivery, and to be released to assume asubstantially larger shape when deployed. Additionally, a frame made ofa shape-memory material will remain substantially elastic in itsexpanded and installed shape. Thus, the IBV can be configured to havesufficient elasticity in its expanded shape to allow the IBV to expandand contract with the expansion and contraction of the bronchial walls180, thereby maintaining the occlusion to distal airflow throughoutrepeated respiration cycles. Additionally, other intra-bronchialocclusion devices can be configured to expand and contract with thetissue of the bronchial walls.

In the illustrated embodiments, the frame 142 comprises six struts 144and five anchors 150. Other numbers of struts and/or anchors canalternatively be used. For example, the number of struts 144 and anchors150 may be equal, and each individual strut may comprise a unitarystructure with an individual anchor member.

The distal ends of the anchor members 150 preferably comprise piercingtips 182 generally configured to puncture tissue of an air passagewaywall 180 to retain the IBV 140 in a desired location within the airway.As shown in FIGS. 4-8, the piercing tips 182 can include stops 184configured to prevent the anchor members 150 from puncturing through thelung tissue 180 beyond a desired depth. The stops 184 can be formed bysplitting the distal ends of the anchor members 150, and bending a firstone of the split sections downward to form the stop 184 as shown, whileleaving a second one 186 of the split sections to extend outwards inorder to puncture a section of tissue.

During inspiration, a substantial air pressure differential can be builtup with a high pressure side on a proximal side of the valve. In theabsence of any anchors, this pressure could potentially force the IBVdistally within the airway. Therefore, it is desirable to anchor the IBVagainst at least distal movement within the airway. In general, the factthat the IBV will allow expiratory airflow in a proximal direction pastthe device means that there will be a substantially smaller pressuredifferential across the valve during expiration (including coughing).Thus, the anchor arrangement including piercing tips 182 and stops 184of FIGS. 4-8 are advantageously arranged to primarily prevent distalmovement of the IBV within the airway. The IBV will also be anchoredagainst proximal movement by the resilience of the anchor members 150and the strut members 144 pressing against the bronchial wall 180. Alsoadvantageously, when the connector rod 170 of the IBV 142 is gripped andpulled proximally to remove the IBV from an airway, the anchors 150 willcollapse slightly, and the piercing tips 182 will release fromengagement with the bronchial wall 180 as the IBV is pulled proximally.

As shown in FIGS. 5 and 6, the proximal ends 190 of the struts 144 curveslightly inwards. This inward curve will further aid in allowing easyremoval of the IBV 140 from an airway by pulling the valve proximally.The inward curve of the proximal strut ends 190 will preferablysubstantially prevent the struts 144 from snagging the tissue of theairway walls as the IBV is drawn proximally.

The curved proximal strut ends 190 will also aid in guiding the IBV 140into a constricting funnel-shaped lumen so as to compress the IBV forloading into a delivery catheter as is described, for example in theSer. No. 10/387,963 application mentioned above. As discussed in the'963 application, one embodiment of loading the IBV into a delivercatheter comprises advancing the IBV, rod-end first into a funnel-shapedconstriction. The inwardly curved proximal strut ends 190 willadvantageously allow the IBV to be smoothly advanced through such afunnel-shaped constriction without damaging the IBV.

As illustrated in FIG. 5, the connector rod 170 extends from the centraljoint 152 proximally through the axial center of the IBV 140. In oneembodiment, the rod 170 is of such a length that it extends beyond theproximal ends 190 of the struts 144 when the IBV 140 is in its expandedshape. The rod 170 can also be of such a length that the rod 170 and thestruts 144 extend substantially the same distance from the central joint152 when the IBV 140 is in a fully compressed state (not shown). Theconnector rod 170 can be made of a biocompatible stainless steel, PVC,or any other suitably rigid biocompatible material as desired. Theconnector rod 170 is preferably sufficiently rigid that when theproximal knob 192 of the rod 170 is gripped, the IBV can be rigidlysupported in a cantilevered manner. The connector rod 170 is alsopreferably configured to facilitate removal of the IBV from an airway bygripping the proximal knob 192 of the rod 170 with standard orspecially-designed forceps and pulling proximally on the rod 170.

The membrane 160 is generally made of a biocompatible polyurethane orother thin, air impermeable material. As shown in FIGS. 2 and 3, themembrane 160 can include tabs 194 which can be folded over the interiorsides 196 of the proximal ends 190 of the struts 144. Covering theproximal ends 190 of the struts 144 with tabs 194 of membrane materialadvantageously prevents the struts 144 from digging into or snagging onthe tissue of the bronchial wall, thereby aiding in removal of the IBVfrom an airway.

The membrane 160 can be formed from a single, flat sheet of airimpermeable material which can be sealed to the frame by adhesives,welds, heat seals or any other suitable manner to create an air-tightseal between a first (proximal) side and a second (distal) side of themembrane. Alternatively, the membrane 160 could be molded orthermoformed into a desired shape which can then be sealed to the frame.

According to an alternative embodiment, the membrane 160 can be formedby placing a mandrel inside the concave space between the struts 144,and then dipping the entire frame 140 into a molten solution of adesired polymer. The frame can then be removed from the molten solution,and the polymer can be allowed to cool, thereby forming a uniformmembrane that substantially entirely encases the struts. In someembodiments, the dipping process can also be employed to form a coatingover each of the distal anchors, thereby substantially preventingcontact between the metallic frame 140 and the patient's airway tissue.This can be advantageous in cases where a patient's tissues rejectnickel-titanium or other material from which the frame is made.

Suitable occlusion devices can be provided in any size or configurationas desired. For example, in some embodiments, one-way valve occlusiondevices having expanded outer diameters of between about 3 mm and about8 mm can be used. Alternatively, valves having outer expanded diametersas small as 1 mm or less could be used.

With returned reference to FIG. 2, a means for delivering anintra-bronchial valve to a target location in an airway of a lung caninclude one of a number of known or newly developed devices. In oneembodiment, means for delivery of an occlusion device to a targetlocation comprises a conventional bronchoscope 30 having a visualizingtip 198 and at least one working lumen 42. A wide variety ofbronchoscopes are commercially available, many of which will be suitablefor carrying out portions of the air leak repair procedure describedherein. Typical bronchoscopes have an outer diameter of about 5 mm,although larger or smaller bronchoscopes could also be used.

Alternatively, any number of other devices could be used in place of aconventional bronchoscope. Specifically, any device that allows aclinician to gain visual and functional access to the interior of apatient's lungs could be used. Such alternative devices could includelaparoscopes, endoscopes, or any other elongate, flexible scope with atleast one working lumen and/or one or more tools mounted on a distal endthereof. In addition to the visualizing capabilities of any bronchoscope(or other scope) that may be used, a clinician may decide to use X-ray,ultrasonic, radiographic, or other visualization systems to providesupplemental visualization during the air-leak treatment procedure.

Suitable means for delivering an intra-bronchial device to a targetlocation often further includes one or more elongate, flexible catheterswith one or more lumens extending therethrough. Suitable catheterspreferably have as small an outside diameter as possible, whilemaintaining sufficient column strength for the catheter to be advancedthrough a patient's airways without buckling or kinking. For example, insome embodiments catheters may be provided with an outer diameter ofabout 2 mm, although larger and smaller catheters can also be used. Atleast one lumen of at least one catheter can be adapted to allow airflowtherethrough. Similarly, at least one lumen of at least one catheter canbe adapted to transmit a liquid therethrough.

Occlusion devices can generally be deployed using any suitablyconfigured catheter. For example, an occlusion device deploymentcatheter can include a distal cavity for retaining at least oneocclusion device to be deployed in a patient's airway and a means fordeploying the occlusion device. A means for deploying the occlusiondevice can include any suitable structure such as a push wire that isextendable through the length of the catheter and can be operated by aclinician to push the occlusion device out of the catheter.Alternatively, the means for deploying the occlusion device couldinclude a retractable sheath that can be retracted relative to theocclusion device, thereby releasing the occlusion device. In anotheralternative embodiment, one or more occlusion devices can be deployeddirectly from a lumen of a bronchoscope without the need for a deliverycatheter. Suitable delivery and deployment devices are described inco-owned and co-pending U.S. patent application Ser. No. 10/052,875filed Oct. 25, 2001 and Ser. No. 10/387,963 filed Mar. 12, 2003, both ofwhich are incorporated by reference and made part of the presentapplication.

Occlusion devices for use with embodiments of the methods describedherein can generally be adapted to be removed from a patient's airwayafter the fistula or other air leak has healed. A means for removing anocclusion device can include an elongate, flexible removal catheter withan occlusion device receiving space, and a means for gripping theocclusion device. The occlusion device receiving space can simply be alumen of sufficient diameter to allow an occlusion device to be drawninto the space. If desired, the occlusion device receiving space can besized to receive a plurality of occlusion devices, thereby eliminatingthe need to remove and re-introduce the removal catheter when removingmultiple occlusion devices. A means for gripping an occlusion device caninclude any suitable trans-lumenal gripping tool, such as biopsyforceps, etc.

Alternatively, a means for removing an occlusion device could simplyinclude a bronchoscope. Accordingly, the occlusion device could be drawninto a lumen of the scope, for example by gripping the connector rodwith standard endoscopic forceps, thereby allowing the occlusion deviceand the bronchoscope to be simultaneously removed. In alternativeembodiments, portions of the occlusion devices can be made from asubstantially bioabsorbable polymer which can be substantially dissolvedand absorbed by a patient's body fluids and tissue, thereby allowingbi-directional airflow to be resumed through a target location withoutthe need for bronchoscopic removal of an occlusion device.

The methods of the present invention can be carried out with the abovedevices or any other tools or devices recognized as suitable by theskilled artisan. One embodiment of the method generally includes:detecting the presence of an air leak in a lung; identifying an airwayleading to a fistula causing the air leak; identifying and marking atarget location within an airway; guiding a means for delivering anintra-bronchial device to the airway in fluid communication with afistula causing the air leak, optionally injecting a substance into theairway distal to the target location, and substantially limiting airleakage by temporarily deploying one or more occlusion devices inselected airways for a sufficient time to allow the tissue surroundingthe fistula to heal and close the air leak, and finally removing theocclusion device at some later time.

Methods of delivering an occlusion device are described in the Ser. Nos.10/052,875 and 10/387,963 applications mentioned above. According to oneembodiment, the occlusion device is loaded into a cavity at a distal endof an elongate delivery catheter. The delivery catheter of thisembodiment is provided with a retractable sheath to surround and retainthe occlusion device. The catheter can then be fed through the workingchannel of the bronchoscope, or otherwise directed to thepreviously-identified target location. Once the occlusion device is inplace, the sheath surrounding the occlusion device can be retracted toallow the occlusion device to expand to its unrestrained shape and size.

As mentioned above, it may be desirable to inject a substance into anairway on the distal side of the deployed occlusion device. For example,such substances could include one or more medicants injected directlyinto an airway or associated with an intra-bronchial device in anyappropriate manner. Co-owned and co-pending U.S. patent application Ser.No. 10/178,073 and Ser. No. 10/317,667, filed on Jun. 21, 2002 and Dec.11, 2002 respectively, teach embodiments of methods and devices fordelivering various medicants and therapeutic substances to a targetlocation of a lung in order to accelerate healing, or otherwise controla biological interaction.

Alternatively, as described in co-owned and co-pending U.S. patentapplication Ser. No. 10/409,785 (“the '785 Application”) filed on Apr.8, 2003, which is also incorporated herein by reference, it iscontemplated that injection of an inflammation-causing substance can aidin causing lung tissue to sclerose and self adhere. Such aninflammation-causing substance could also be used in treating an airleak by promoting sclerosis and healing of the lung tissue in thevicinity of the injected substance. According to one embodiment asdescribed in the '785 application, the inflammation-causing substanceinjected into a lung portion can comprise or consist of autologous bloodor a constituent thereof.

Alternatively still, other organic and non-organic substances, gaseousor liquid, heated or cooled, may be used to cause inflammation of thelung tissue adjacent to a fistula. For example, U.S. Patent ApplicationPublication No. 2001/0051799 to Ingenito (incorporated in its entiretyherein by reference, shows and describes a number of fibrosis-causingsubstances. Hot saline solution or very cold liquids or gasses may alsobe used.

In some situations it might be necessary to occlude an airway that feedsa substantial portion of healthy lung tissue in addition to the damagedsection. It is preferred that the placement of the occlusion deviceswill occlude a minimum of airways extending through healthy lung tissue.

Once the occlusion device deployment and any substance-injectionprocedures have been completed, the bronchoscope and any othertrans-bronchial tools can be withdrawn from the patient, thus leavingthe occlusion device(s) and any injected substance in place relative tothe fistula. The procedures described herein allow the patient to beambulatory while the fistula heals. Depending upon the patient, theamount of damage and the particular substance injected (if any), thetime required for the fistula to heal will vary. The occlusion device(s)can be removed after a clinician has verified that the fistula hassubstantially healed. Verification of air leak healing can beaccomplished by evaluation of a patient's symptoms, testing a patient'sbreathing function (e.g. breathing effort, etc), and/or by imaging of apatient's lungs such as by x-ray or MRI scans.

Once the air leak has healed, a suitable means for removing an occlusiondevice can be introduced through the patient's airways to a positionadjacent an occlusion device. Once in position, the means for removingan occlusion device can be operated in an appropriate manner to removeone or all of the occlusion devices. Multiple occlusion devices can beremoved in any suitable sequence, and if desired, without removing abronchoscope with each occlusion device. In an alternative embodiment, aframe and/or a membrane of an occlusion device can comprise abio-absorbable polymer, which can be left in place and allowed todeteriorate, thereby “removing” the occlusion device from the path ofair flow in the target section without introducing a bronchoscope or aremoval catheter.

Although certain embodiments and examples have been described herein, itwill be understood by those skilled in the art that many aspects of themethods and devices shown and described in the present disclosure may bedifferently combined and/or modified to form still further embodiments.Additionally, it will be recognized that the methods described hereinmay be practiced using any device suitable for performing the recitedsteps. For example, the target location air leak could be treated by thepresent method in combination with conventional open-chest orthoracoscopic surgical procedures. Such alternative embodiments and/oruses of the methods and devices described above and obviousmodifications and equivalents thereof are intended to be within thescope of the present disclosure. Thus, it is intended that the scope ofthe present invention should not be limited by the particularembodiments described above, but should be determined only by a fairreading of the claims that follow.

What is claimed is:
 1. A method of manufacturing an airway occlusion device, the method comprising: shaping a piece of superelastic material into an hourglass shape having a first end and a second end, wherein: the first end comprises two or more struts; the second end comprises two or more anchors; and the first end and second end are connected by a substantially cylindrical center portion; and covering the struts with an air impermeable membrane, wherein the piece of superelastic material is a tube and at least one of the struts or the anchors are formed by making axial cuts along the tube.
 2. The method of claim 1, wherein the hourglass shape is an asymmetric hourglass shape.
 3. The method of claim 1, wherein the superelastic material is Nickel-Titanium.
 4. The method of claim 1, wherein the piece of superelastic material is shaped using machining.
 5. The method of claim 1, wherein the piece of superelastic material is shaped using molding.
 6. The method of claim 1, wherein the struts are formed by making axial cuts along the tube.
 7. The method of claim 1, wherein the piece of superelastic material is sections of wire.
 8. The method of claim 1, further comprising heat treating the superelastic material.
 9. The method of claim 1, further comprising attaching a connector rod to the substantially cylindrical center portion, wherein the rod extends toward the first end.
 10. The method of claim 9, wherein the connector rod is attached using press fitting.
 11. The method of claim 9, wherein the connector rod is attached using adhesives.
 12. The method of claim 9, wherein the connector rod is attached using welds.
 13. The method of claim 9, wherein the connector rod is made of a biocompatible stainless steel.
 14. The method of claim 1, further comprising splitting the distal ends of the anchor members and bending a first one of the split sections downward to form a stop, while leaving a second one of the split sections to extend outwards.
 15. The method of claim 1, wherein the membrane includes tabs which can be folded over the interior sides of the proximal ends of the struts.
 16. The method of claim 1, further comprising sealing the membrane to the frame using adhesives.
 17. The method of claim 1, wherein covering the struts with an air impermeable membrane comprises placing a mandrel inside the concave space between the struts and then dipping the piece of superelastic material into a molten solution of a desired polymer.
 18. The method of claim 17, further comprising dipping the anchors into a molten solution of a desired polymer. 